Figure 2. PD-L1 representative pictures by immunostaining in ESCC. (A) Negative pattern for PD-L1; (B) Positive pattern for PD-L1; (C) the positive control staining (Placental tissue). Abbreviations: ESCC: Esophageal Squamous Cell Carcinoma; PD-L1: Programmed Death-Ligand 1.